Medicare Supplement

How Medigap plan letters function for Dallas Medicare

DALLAS, Texas — If you're new to Medicare, or helping a parent sort through the mail piling up on the kitchen table, one term keeps coming up: Medigap. It's also called Medicare Supplement insurance, and it's one of the most misunderstood pieces of the Medicare puzzle.

Here's a plain-English guide to what Medigap actually does, how the lettered plans work, and where it fits alongside the rest of your Medicare coverage.

What Medigap is — and what it isn't

Medigap is private insurance that helps pay some of the out-of-pocket costs that Original Medicare (Part A and Part B) leaves behind. Think of the coinsurance, copayments, and deductibles that Medicare doesn't fully cover. A Medigap policy picks up part or all of those, depending on which plan you choose.

A few things Medigap is not:

• It is not Medicare Advantage (Part C). You cannot have both a Medigap policy and a Medicare Advantage plan at the same time.
• It does not include prescription drug coverage. For drugs, you'd add a stand-alone Part D plan.
• It generally does not cover dental, vision, hearing aids, or long-term care.

Medigap works alongside Original Medicare. Medicare pays its share of an approved claim first, then your Medigap policy pays its share.

How the standardized letters work

Here's the part that trips people up. In most states, Medigap plans are standardized by the federal government and labeled with letters: A, B, C, D, F, G, K, L, M, and N. (Massachusetts, Minnesota, and Wisconsin have their own systems.)

The key idea: a Plan G sold by one company covers the same core benefits as a Plan G sold by another company. The letters describe the benefits. What can differ between carriers is the price, customer service, and extras.

A quick tour of what the letters generally cover, according to Medicare.gov:

• Plan A — the most basic set of benefits.
• Plans B, D, G, M, N — build on that base in different ways.
• Plan G — one of the most comprehensive options available to people newly eligible today. It covers the Part A deductible and most other gaps, but not the Part B deductible.
• Plan N — similar to G, but you may pay small copays for some office and ER visits.
• Plans K and L — cost-sharing plans with lower premiums and yearly out-of-pocket limits.
• Plans C and F — no longer available to people who became eligible for Medicare on or after January 1, 2020. If you were eligible before that date, you may still be able to buy them.

For a side-by-side chart, the official comparison lives at Medicare.gov under "Compare Medigap plan benefits."

When to enroll — and why timing matters

The best window to buy a Medigap policy is your Medigap Open Enrollment Period: the six months that start the month you're 65 and enrolled in Part B. During that window, insurance companies can't turn you down or charge you more because of health conditions.

Miss that window, and in most states carriers can use medical underwriting — meaning your health history can affect whether you're accepted and what you pay. There are some exceptions and "guaranteed issue" rights, but they're narrow. This is why so many Medicare counselors urge people not to sleep on that initial six-month period.

How Medigap fits with Part D and Medicare Advantage

Medigap pairs with Original Medicare. If you also want drug coverage, you'd typically add a stand-alone Part D plan. A few 2026 program-level numbers worth knowing:

• Part D out-of-pocket cap is $2,100 in 2026.
• Part D maximum deductible is $615.
• The old coverage gap ("donut hole") is gone; Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread drug costs across the year in monthly amounts.
• IRMAA surcharges on Part B and Part D start above $109,000 in income for a single filer in 2026.

If you go the Medicare Advantage route instead, drug coverage is usually built in, and Medigap does not apply.

What this looks like in Dallas

Dallas is in Dallas County, where Medicare beneficiaries generally have a wide range of both Medicare Advantage plans and stand-alone Part D plans to choose from during Annual Enrollment. Medigap is a little different: because the plans are standardized by letter, the shopping question is less "which plan letter is offered here" and more "which carriers sell that letter in Texas, and at what price."

The Texas Department of Insurance publishes rate comparison information for Medigap policies sold in the state, and it's worth a look before you commit.

Key dates to keep on the fridge

• Medigap Open Enrollment: the 6 months starting when you're 65 and enrolled in Part B.
• Medicare Annual Enrollment Period: October 15 – December 7 (for Part D and Medicare Advantage changes).
• Medicare Advantage Open Enrollment: January 1 – March 31.

Medigap itself doesn't follow the fall AEP calendar — you can apply any time, but outside your initial window you may face underwriting.